The present invention relates to a tobacco smoking mixture. In particular, the invention relates to a tobacco smoking mixture, for a smoking article such as a cigarette, which includes at least one inorganic particulate material. The inorganic particulate material is present in an amount effective to reduce the temperature of a burning portion of the tobacco smoking mixture upon combustion/pyrolysis thereof. The present invention also relates to methods for manufacturing such novel tobacco smoking mixtures.
Tobacco smoking mixtures and/or smoking articles are disclosed in U.S. Pat. Nos. 3,545,448; 3,885,574; 3,943,942; 4,008,723; 4,019,520; 4,119,104; 4,452,259; and 5,345,955, the disclosures of which are hereby incorporated by reference.
Carbon and graphitic foams and methods of manufacturing carbon and graphitic foam materials are disclosed in U.S. Pat. Nos. 3,960,770 and 6,261,485. The ""485 patent discloses carbon foams useful at high temperature and a process of making graphitic foam from a mesophase or isotropic pitch.
While there have been proposals in the prior art for modifications to tobacco smoking mixtures to include inorganic material, such proposals lead away from the present invention wherein a tobacco smoking mixture includes at least one inorganic particulate material which is present in an amount effective to reduce the temperature of a burning portion of the tobacco smoking mixture upon combustion/pyrolysis thereof.
The invention provides a tobacco smoking mixture which includes tobacco and at least one inorganic particulate material, wherein the at least one inorganic particulate material is present in an amount effective to reduce the temperature of a burning portion of the tobacco smoking mixture upon combustion/pyrolysis thereof. According to a preferred embodiment, the at least one inorganic particulate material comprises a material selected from the group consisting of an inorganic carbonate, an inorganic hydrate, an inorganic oxide, an inorganic phosphate, a carbon material and combinations thereof. The inorganic carbonate may comprise calcium carbonate, magnesium carbonate or combinations thereof. The inorganic oxide may comprise any suitable metal oxide such as, for example, titanium oxide, aluminum oxide, or the like. The carbon material may be selected from the group consisting of graphite, graphitic foam, carbon foam, fullerene, activated carbon and combinations thereof. The at least one inorganic particulate material is present in an amount effective to reduce the temperature of a burning portion of the tobacco smoking mixture, preferably to less than or equal to about 750xc2x0 C., more preferably less than or equal to about 600xc2x0 C. The at least one inorganic particulate material preferably comprises from an effective amount up to about 75% by weight based on the total weight of the tobacco smoking mixture.
According to another preferred embodiment, the tobacco smoking mixture comprises a tobacco smoking rod of a cigarette, and wherein the tobacco rod is preferably surrounded by a wrapper and an optional filter is at one end of the cigarette.
The invention also provides a method for manufacturing a tobacco smoking mixture for use in a smoking article, comprising the step of spraying tobacco with at least one inorganic particulate material, wherein the at least one inorganic particulate material is added to the mixture in an amount effective to reduce the temperature of a burning portion of the tobacco smoking mixture upon combustion/pyrolysis thereof.
The invention further provides a method for manufacturing a tobacco smoking mixture for use in a smoking article, comprising the steps of mixing at least one inorganic particulate material with tobacco, and casting the mixture into a sheet, wherein the at least one inorganic particulate material is added to the mixture in an amount effective to reduce the temperature of a burning portion of the tobacco smoking mixture upon combustion/pyrolysis thereof.